1. Field of Invention
The present invention relates to a waterproof connector.
2. Description of Prior Art
In an ordinary connector, a plurality of terminal storage chambers are formed in the interior of a connector housing and terminals are inserted from the rear portion thereof. In the connector of this type, especially, in the connector housing thereof to be used in a place which requires a waterproof condition, waterproofing means is provided in the rear portion of each of the terminals to be inserted into their respective terminal storage chambers. As an example of such technique, there can be taken a technique which is disclosed in Unexamined Japanese Utility Model Publication No. Sho.61-26272. In this technique, cylindrical rubber plugs are respectively fitted with electric wires to be connected to the terminals and the rubber plugs are made to come into contact with the whole peripheries of the inner walls of the terminal storage chambers to thereby secure a sealed condition between the rubber plugs and the terminal storage chambers. More specifically, a metal terminal is fixed to the leading end portion of a wire and a rubber plug having a plurality of pleats on the outer periphery thereof is disposed in the rear of the metal terminal and is staked and fixed by the terminal fitting. And, as the terminal fitting is inserted into a terminal storage chamber formed in a connector housing, the pleats of the rubber plug are made to come into close contact with the peripheral wall of the terminal storage chamber, thereby sealing a clearance between the wire and the peripheral wall of the terminal storage chamber. Further, as a countermeasure to prevent the terminals from being removed from their respective terminal storage chambers, a retainer is mounted to the rear portion of the connector housing. The retainer includes a securing claw, that is, the retainer can be mounted to and removed from the connector housing by means of engagement and disengagement of the securing claw with respect to the housing. Also, in order that the retainer can be inserted in a direction perpendicular to the respective electric wires while avoiding interference with the wires, the retainer includes a plurality of slits which are respectively opened downwardly and are arranged in parallel to one another. Further, a pair of flexible projections are projectingly formed in the opening edges of each of the slits in such a manner that they are opposed to each other with the slit between them. This structure makes it possible not only to press against the rear end of the rubber plug but also to clamp the electric wire from the right and left sides of the wire substantially by one half of the whole periphery of the wire.
In the conventional waterproof connector of the above-mentioned structure, if the rear end face of the rubber plug and the rear opening edge of the terminal storage chamber are not level with each other when the metal terminal is mounted to the housing, then there is a possibility that there can be produced a clearance between the pleats of the rubber plug and the peripheral wall of the terminal storage chamber and standing water can enter the clearance between them although the water does not enter at once. In view of this, the present applicant has proposed in a previous patent application a waterproof connector having an end terminal plug in the rear end portion of the rubber plug for closing the rear opening edge of the terminal storage chamber.
Describing this by use of FIGS. 4 and 5, a rubber plug 31 is formed in a substantially cylindrical shape and includes two flange-like pleats 32 in the axially central portion thereof and, at the same time, includes in the rear end portion thereof an end terminal plug 33 which is used to close the end edge of a rear opening formed in the terminal storage chamber. The end terminal plug 33 is formed in an umbrella shape which fans out outwardly.
In this structure, an electric wire 35 is inserted through a central hole 34 formed in the rubber plug 31 and the portion of the wire 35 projecting out of the front end of the central hole 34 is stripped to expose core wires 36. The thus exposed core wires 36 are fixed by staking a pair of wire barrels 38 provided in a metal terminal 37, while the respective leading end portions of the rubber plug 31 and the covering material of the wire 35 are fixed by staking a pair of insulation barrels 39. In this state, if the wire with the rubber plug 31 mounted thereon is inserted into a terminal storage chamber 42, then a lance 43 provided on the bottom surface of the terminal storage chamber 42 is fitted into and secured to a securing hole 44 formed in the metal terminal 37. In this manner, the pleats of the rubber plug 31 are made to come into close contact with the peripheral wall of the terminal storage chamber 42 and, at the same time, the end terminal plug 33 closes the rear opening edge 42a of the terminal storage chamber 42, thereby being able to perform a positive sealing function.
In the above-mentioned structure, in order to satisfy the securing of the metal terminal 37 and the closure of the rear opening edge 42a of the terminal storage chamber 42 by the end terminal plug 33 of the rubber plug 31 at the same time, it is necessary to control the securing hole 44 of the metal terminal 37 and the end terminal plug 33 of the rubber plug 31 in such a manner that a given distance must be always kept between them. However, conventionally, it is known that such dimensional control can vary. As the primary cause of such variable dimensional control, it can be pointed out that the metal terminal is caused to extend in the longitudinal direction thereof when the wire barrel 38 is staked. In this case, the distance between the securing hole 44 and the end terminal plug 33 is increased. Also, as the other cause, it can be imagined that, when the insulation barrels 39 are staked, the setting of the insulation barrels 39 are originally shifted from their respective normal positions with respect to the rubber plug 31 to thereby result in the increased variation of distance between the securing hole 44 and the end terminal plug 33. Or, it can be also imagined that such increased variation of distance between the securing hole 44 and the end terminal plug 33 may be caused by the dimensional errors of the respective components of the waterproof connector.
If the distance between the securing hole 44 and the end terminal plug 33 is increased due to the above causes, then even when the metal terminal 37 is inserted into the terminal storage chamber 42 and is then secured by the lance 43, as shown in FIG. 5, the metal terminal 37 cannot reach the end terminal plug 33 of the rubber plug 31 and the rear opening edge 42a of the terminal storage chamber 42. Thus, the metal terminal 37 is not in contact with the rear opening edge 42a, thereby spoiling the sealing function of the end terminal plug 33.
The wire that is drawn out from the connector can be drawn out laterally for reasons of wiring. Then, the wire is given a lateral tensile force, which in turn has an influence on the rubber plug, so that there can be generated a gap between the inner walls of the terminal storage chamber and the rubber plug. In such a structure as disclosed in the above-mentioned publication in which there is provided the flexible projection, the wire is held backwardly of the rubber plug by a distance corresponding to the amount of projection of the flexible projection. Therefore, it can be said in a sense that the influence of the tensile force on the rubber plug can be eliminated to thereby prevent generation of the above gap between the inner walls of the terminal storage chamber and the rubber plug.
However, strictly speaking, such structure is truly effective when the wire is drawn out in a direction where the flexible projection is provided but, according to cases, such projection cannot be provided in a direction perpendicular to this direction. That is, according to the draw-out directions of the wire, there is a possibility that the tensile force of the wire can have an influence on the rubber plug to produce a gap between the rubber plug and the terminal storage chamber, thereby being unable to secure a sealed condition between them.
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional waterproof connector.